Dependence of the b-wave on the potassium concentration in the isolated superfused rabbit retina.

The amplitude of the b-wave of the isolated superfused rabbit retina is drastically reduced with increasing potassium concentration (10 and 20 mM respectively) in the perfusate like in frog retina. These results are in agreement with the idea of the glial origin of the b-wave, but an influence of potassium on synaptic transmission remains a possibility. For these results the conditions for tissue survival are imperative. When the retina was superfused with a plasma saline mixture kept at 35 degrees C, b-wave amplitudes for different preparations varied between 300 microV and 900 microV and loss of sensitivity was tolerated till 15% in one preparation. The temperature quotient for the amplitude of b-wave was 4-6 between 35 degrees and 25 degrees C, for the peak time about two.